Hydropneumatic recuperator for guns



, 4 She ets-Sheet 1 Nov. 6, 1951 J. E. PRACHE HYDROPNEUMATIC RECUPERATOR FOR GUNS Filed April 25, 1947 [NJ/EN TOR A TTORNEYS' v W, {Mm em J. E. PRACHE HYDROPNEUMATIC RECUPERATOR FOR GUNS Nov. 6, 1951 4 Sheets-Sheet 5 Filed April 25, 1947 k Em 17V I/E/V 7012 Jacym [WI/Mien Prache ATTORNEYS Nov. 6, 1951 J. E. PRACHE HYDROPNEUMATIC RECUPERATOR FOR GUNS 4 Sheets-Sheet 4 'Filed April 25, 1947 Jacyues EmzlLenPrache @wflm, Wad/aim A T TOR/YE YS Patented Nov. 6, 1951 Jacques Emilien Prache, Fontenay-sous-Bois, a .7 France, assignor to Schneider & Cie, Paris,

France, a joint-stock company of France Application April'25, 1947, Serial No. 743,998 In France April 26, 1946 This invention concerns hydro-pneumatic or pneumatic recuperators, which are more particularly intended for pieces of artillery having a large vertical field of fire, and has for its objectto provide means which permit inter alia of auto- Claims. (CI. 89-43) 2 nated by V0, its final volume after a given recoil L by V1, and the ratio matica'lly'regulating, as a function of the angle of fire, the power of braking and of returning into battery position possessed by these recuperators without modifying their initial latent energy.

It-hasaIready been'proposed to vary the power of such recuperators as a function of the laying angle by acting on the initial pressure of the compressed'air contained in-the air reservoir, this being efiected by delivering into the said reservoir, by: means connected withthe elevating mechanism, variable quantities of the liquid contained in-the hydraulic cylinder associated with the said reservoir so as to reduce the volume occupied by said air.

However, it-will readily be understood that at increasing laying angles the control of the operation of delivering liquid into a reservoir containair under high pressure by the elevating operation superposes a considerable additional load on the normal elevating force whereas, on the contrary, with-decreasing laying angles, the ex-- pansion of the aforesaid air is capable of imparting a dangerous acceleration to the oscillating mass.

These disadvantages are radically eliminated by the present invention, owing to the fact that the desired variation of power is only prepared during the laying in elevation and only becomes effective upon firing, this double result being obtained, according to the essential feature of the said invention, by regulating the initial volume of'air subjected to compression at the recoil (which may be designated as the useful air) as a'function of the laying angle, but without changing its pressure. In other words, it is not then the initial latent energy of the recuperator which is rendered dependent upon the laying in elevation since this remains constant at all angles, but its potential energy, that is to say, that which it-willsto're up at the recoil. It will hereinafter be seenthat the variation of volume in question may be obtained with a minimum expenditure of force.

It can moreover readily be shown that this mere variation of the initial volume of the gas as a function of the laying angle permits of inversely varying the energy accumulated by the recuperatorfor a given recoil.

If. in fact, the initial volume of the air is desi by K, while its initial thrust is designated by F5, it is known that the energy stored up Tr is expressed by:

K T,--FOLKTI' which shows that Tr varies proportionately to K 2: log K creases, as can readily be verified.

Now, the volume Vo being established for the minimum angle, if for a given laying angle a a certain volume v is cut off therefrom, the initial that is to say of K.

Since the value of K has increased with the increased gun elevation or laying angle, it is deduced therefrom with reference to the Equation 1 that the value of Tr has itself increased.

In practice, the variation of the initial volume reserved for the useful air may be continuous as a function of the laying angle, or may be effected step by step, which is' sufficient in practically all cases.

An example of the embodiment of each of these two conceptions is illustrated in the accompanying drawings, as applied to a recuperator of the type constituted by a cylinder filledwith liquid, which cylinder is independent of the brake cylinder and in which there moves a piston which, at the recoil, delivers the said liquid into a compressed-air reservoir.

Figure l is a diagrammatic sectional elevation of a hydro-pneumatic recuperator in which the initial volume occupied by the useful compressed air varies continuously as a function of the laying angle.

Figure 2 shows a variation of the same arrangement.

the value of this product increasing when K in- "cys /4,059

3 Figure 3 is a similar section of a recuperator in which the initial volume of useful compressed air varies discontinuously. I Figure 4 is a diagrammatic sectional elevation of a modification of the recuperatorshown in Figure 1. 1 v

' In the form of embodiment illustrated in Figure 1, the recuperator is constituted by a cylinder I coupled with a cradle 2 which oscillates during vertical laying about horizontal trunnions 3 sup ported by the carriage l. In this cylinderzmoves' a piston 5 coupled with the recoiling part 6, the said piston delivering the liquid at; the; recoil from the cylinder into a compressedwair reservoir;

1 connected to the cylinder I and communicating freely therewith through a channel 8. As shown, the channel 8 and the portion of cylinder-[flying to the rear (to the right as viewed in the drawing) of piston 5 are completely filled with-liquid, while. the portion of cylinder I; in front of piston 5 is ven e t he tmesnhere thr u h n. r f ce a.. According to the invention, the; cylindrical ca-.. pacity of the air reservoir 1 is divided into two compartments a and b by a piston 9, the rod 9a, of which extends in an air-tight manner through therear end of theyair reservoir and supports, at. its extremity a roller, IQarranged so, as tetra-verse;- a guide groove I I during laying in elevation,;the said groove being connected to the carriage and suitably profiled. The separating piston 9 is provided with a conduit 9b in which there is fitted. a check valve limaintained in the seated position when the gun is in battery by a spring 14 of weak tension, thus permitting communication between the two compartments a andlb I. I

When the cradle 2, under the'action 10fthe elevating mechanism, is subjected to a positive angular displacement about thetrunnions 3,: the roller II], rolling in the groove I I, causes the piston Ste slide towards the front of the reservoir 11' The chambers a. and b remain in communication with one another during-theentire displacement, the spring I4 being so calibrated asto'maintain' the valve I3 in the open position even when the angular laying velocity is. at a maximum. There is an exchange of gas, between a and b; without any variation of pressure, thetotal'volumeremaining constant exceptv for the negligible variation due to the penetration of the rod 92, of small diameter. The chamber a which, as will hereine; after be seen, is intended to. confine the initial useful volume Vqof gas, consequently changes in volume as a function oi the inclination, according to the law imposed by the profilew of the guide groove II.. H The barrel being laid at. any angle, when. the firing takes place, the, recoiling mass, B. carries along the recuperator piston 5 which delivers a. certain quantity of liquid from thecylind'er. I' into the compartment a. The pressure in'this compartment suddenly rises and causesthe valve I3 to close immediately, the result of which is to place the chamber bout of circuit i. e., .outoi' communication withithe chamber a,. Thecomjei pression of the recuperator and consequently the energy stored up during the recoil therefore depend solely upon the volume of the chamber at, the laying angle inv question, and it, has hereinbefore been'seen that this energy varies inversely with the variation of the initial volume of the said capacity. I 7

During return into battery position, the liquid; 7 is delivered into the cylinder I by-the expansion of the gas confined in the chamber a, the pressure; 7

massv oscillating: during the laying in elevation ensan in t e a d Qi vo r T 4 l of which, while decreasing progressively, never theless remains greater'than that existing in b until the return into battery position is cornpleted. The valve. I3 therefore remains closed until the return into the initial position. At this moment, the pressures at. and b. balance one another and the valve opens,fre.es tablish ing the communication between the ,two compartments.

it will readily be seen that during the laying operation the isplacement of the piston! only;

'requiresthe-small effort necessary for overcoming the passive resistances and the initial pressure of the gaS acting on the single cross section ofthe. ITQd'Qa. of;the, said piston. This latter part of'theleffortimay even be eliminated by the addition of a compensating rod I5 of equal diameter to thel rod 'lj, on the opposite face of the piston,

as indicated in Figure 4. 7

As will be seen fromthe variation illustrated in Figure 2, the communication between the compartments a. and b may be eiiected, through-a conduit; I-l the-wall ofth air reservoir I, .t piston- 9= then being solid. 7

Inrder; t0-1av r e a closure o t1 1. .-'seid. valve under theinfluenceof an: ncrease. in' pre 1. suredue. to amore rapid'temperatureincrease r a thanin-lna cock Ifiisdisposed'n the. pond 'tg Ii. connecting the two compartmentsl a and,. b. regardless, of; the position of the pistons This cock I6 will be controlled positively, for. example. by fa dog-1 18, having -tWofunegudl 'i rench tnsee-met the sceilieegmes 1 6 andacts on crankIS Qfafilflfisfiid; cock.

the. battery position, thecock is maintaine open and, assoon as the recoil icommen ces ituis 7 closed by the. iorwardor shorter .b fanch oi, the, a

dog. I8 which after' the cl o sing leaves, the crankg, Upon return intobattery position,.-it;is the rear branch, that is to say the longer which acts. .o rr.

the crank I9 and reopens the cock. I I It is; obvious that any other automatic. valve, cock device or slidevalve; having a. posit Ql-FmQiXr ad pted In, the e bodiment illustrated in. Figure the constituted-by the same elements, designated the same reference numerals, aslthoseshown 1v he p ced ng: figures; but in hi c e he reset? voir; 'I,, is subdivided permanently by nxedparti tions into a number of compartments a, b, c,,,d..-,- The aforesaid separating piston!!- is then; replaced by a. multipleslide. valve designed to-establish ori interrupt, communication between the. various; aforesaid compartments, Thislslidevalve is, con; uted y a r lu -sl n in aflu r-t shtma ner in orifiees located in alignment: in the pa eds ontrolle by he an ular di l em ntg f. the oscil atin mass hrou h ll r UL. which is made to tra er eh fi ed r ove.- th "LE- e."

' ms c r spond tcpredeterminedlavin an les:

1. 513', and are; separated by sections men- 1 tric. t0. the trun-nions 'Qhannels;zflsi'Leflrzare provided intherod 9a. atithez'points; atwhibhwifi passesthroughthe various: partitions}. so: as: to; i ensure the. intereco'mmunication. of 1 allethe; coma partments .during. the laying; of 1 amplitudeqm Their lengths arelsuch thattheusucce'ssive ins; creasing displacements of the rod 9a by the cam groove I. I; .ensurethe placing outof circuit; firstiof all of the compartment 11' and then of the-iollowe ing compartment c and finallyof the thirdcome partmentb; so asto: pass in'stages from-,the'complete chamber a+b+c+d forthe minimum layingv angle to the single compartment a'iorthe recuperatorl- Naturally, the control of the slide-valve 3.

could be obtained by other means than a cam connected to the carriage, and'could also be rendered dependent, not upon the laying of the barrel with respect to the carriage, but upon the angle of fire in the particular case where the platrem on which the carriage is mounted is'itself adapted toundergo considerable deflections from the level position, whichis the case in particular with armoured. vehicles It is, in fact, obvious that the regulation of the initial volume oi the useful air would then have to be a function of the true inclination of the barrel with respect to the true horizontal or to the true vertical.

Finally, it must be understood that the invention covers any other arrangement of the component chambers enclosing the air under pressure in which means are provided for placing one or more of these chambers in or out of circuit, and that such means could, for example, be controlled by the laying of the barrel in elevation.

Regardless of the method of application adopted, it is to be observed that if it is assumed that the law of variation of the initial volume of the useful air is assumed to be established principally with the object of rendering the recoil uniform, there will be obtained as a secondary advantage a certain regulation of the duration of the return into battery position and vice versa.

In fact, as has been shown, the energy accumulated in the recuperator during the recoil is greater in proportion as the angle or laying is greater and that consequently during the return into battery position the resistant work of the force of gravity is greater. The energy available and the resistant work therefore vary in the same sense, which tends to render the return accelerations uniform.

Although the invention has hereinbefore been described exclusively in its application to a recuperator of Variable power intended to co-operate in the braking of the recoil and to ensure the return of the recoiling mass of pieces of artillery into battery position, it will be clear to any person skilled in the art that it is also applicable to accumulators of hydro-pneumatic or pneumatic energy employed for other purposes when it is necessary to vary their power. Thus, for example, again in the sphere of artillery, it may be applied directly to hydro-pneumatic or pneumatic rammers for the round, which are directly influenced by the laying movements of the barrel and placed under tension at the recoil.

I claim:

,1. In a recoil system for a moving mass which is adapted to be moved to various angular positions relative to the horizontal, a cylinder, a piston in said cylinder, a piston rod secured to said piston and to the moving mass, a second cylinder in free communication with said first named cylinder, a piston in said second cylinder intermediate the ends thereof, a piston rod for said second piston, a conduit connecting the portions of said second cylinder lying on opposite sides of said second piston, a normally open valve in said conduit, means controlled by the moving mass for closing said valve during each recoil movement of said mass and means connected to said second piston rod for varying the position of said second piston according to the angle of elevation of the moving mass.

2. In a recoil system for a un, a cylinder, a

piston in said cylinder, a piston rod secured to said piston and to a 'recoiling portion ofsaid gun,"

a second cylinder. in free communication with said first cylinder, a piston in said second cylinder intermediate the ends thereof, a normally open passageway through said second piston c0nnecting the portions of said second cylinder lying on opposite sides of said piston, means for automatically closing said passageway during each. recoil movement of the gun and means for vary--- ing the position of said second piston according.

to the elevation of the gun. I

3. In a recoil system for a gun, a cylinder, a piston in said cylinder, a piston rod secured to said piston and to a reeoiling portion of said gun, a liquid in said cylinder, a second cylinder in free communication with said first cylinder, a gaseous medium in said second cylinder compressible by the liquid displaced from said first cylinder by the movement of said first piston during recoil and means for decreasing the eifective volume of said second cylinder as the elevation of the gun is increased without change in the initial pressure of said gaseous medium.

4. A system as described in claim 3 in which said means includes a piston mounted in said second cylinder, a normally open port through said piston and valve means for closing said port during recoil of the gun.

5. A system as described in claim 3 in which said means includes a piston mounted in said second cylinder, a piston rod for said second piston, a cam secured to the gun carriage and engaging said second piston rod, a normally open port through said second piston and means for closing said port during recoil of the gun and maintaining said port closed until the gun returns to battery.

6. A system as described in claim 3 in which said means includes a piston mounted in said second cylinder, a normally open by-pass around said second piston, valve means in said by-pass and means for closing said valve means during recoil of the gun.

7. A system as described in claim 3 in which said means includes a piston mounted in said second cylinder, a piston rod for said second piston, a cam secured to the gun carriage and engaging said second piston rod, a normally open by-pass around said second piston, a valve in said by-pass and automatic means for closing said valve during recoil of the gun and for reopening said valve as the gun returns to battery.

8. A system as defined in claim 3 in which said means includes at least one partition in said second cylinder having a normally open port therein and valve means actuated by the elevation of the gun for closing said port.

9. A system as defined in claim 3 in which said means includes a plurality of axially spaced partitions in said second cylinder having ports therein, a valve rod sliding in said ports and a cam secured to the gun carriage and engaging said valve rod, said valve rod being so constructed and arranged that said ports will be open when the gun is not elevated and will be successively closed as the gun is elevated.

10. In an accumulator of hydro-pneumatic or pneumatic energy of the variable power type wherein the accumulation of energy results from recoil movement of a movable mass and the amount of energy accumulated varies with the position of said mass prior to recoil, a cylinder, a piston in said cylinder, a piston rod connecting said; piston, to. said mass; 510 as tojifiov said piston in thecylinder in aqcordance' with the recoil movementsmf said mass; a second-cylinder infree:

communication withsaid first. cylinder, said sew; ondi cylinder:- being partially filled; with: a, 'compre'ssible fluida medium, the remainder'of said 'second" cylinder and. the portionof said first cylinder in fireev'communicati-on therewith containing. a,

Without simul taneousl-y varying the pressure'of" said compressible fluidmedium.

' JACQUES EMILI'EN' PRACHE;

wmgase v REFERENCES em m- The following references are of Nimiber me T 1,486,992: J9me: 8 924;:-

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